Machine tool

ABSTRACT

A machine tool including a movable spindlehead member having a rotatable tool spindle member reciprocable lengthwise parallel with its axis of rotation, and a work-supporting compound slide assembly having two slide members movable in directions at right angles to one another. All members can be selectively moved at feed and traverse rates in opposite directions by variable speed motors, one connectable to the spindlehead or the tool spindle and the other to either of the two slide members of the worksupporting compound slide. The motors are connected to their respective tool and work-moving members through discrete transmissions of the continuously meshed gear type under the control of hydraulically actuated clutches. Spindle feed is alternatively provided from a spindle drive motor to correlate feed with rotation. The tool spindle is provided with springbiased mechanism for engaging a tool arbor having a tapered shank and retaining the same in a suitable tapered tool arbor socket provided in the front or tool end of the spindle and fluid pressure actuated compound motor means for releasing the tool arbor from the spindle arbor socket.

llnited States Patent Wolf 51 Mar-20,1972

[541 MACHINE TOOL Heinz K. Wolf, Willoughby Hills, Ohio [73] Assignee:The New Britain Machine Company, New

Britain, Conn.

[22] Filed: Jan. 30, 1970 [21] Appl. No.: 7,194

[72] inventor:

[52] US. Cl ..90/ll D, 408/239 A [51] Int. Cl. ..B23c 1/00 [58] Field ofSearch ..90/1 1 A, ll D; 60/54.5;

I 408/238, 239 R, 239 A, 240

Primary Examiner-Gerald A. Dost Attorney-David S. Urey, Alan C. Rose andAlfred B. Levine p Ill 1R 1: l llll W20 z 0 i 9! i fi;;,ii" aw W [5 7]ABSTRACT A machine tool including a movable spindlehead member having arotatable tool spindle member reciprocable lengthwise parallel with itsaxis of rotation, and a work-supporting compound slide assembly havingtwo slide members movable in directions at right angles to one another.All members can be selectively moved at feed and traverse rates inopposite directions by variable speed motors, one connectable to thespindlehead or the tool spindle and the other to either of the two slidemembers of the work-supporting compound slide. The motors are connectedto their respective tool and workmoving members through discretetransmissions of the continuously meshed gear type under the control ofhydraulically actuated clutches. Spindle feed is alternatively providedfrom a spindle drive motor to correlate feed with rotation. The toolspindle is provided with spring-biased mechanism for engaging a toolarbor having a tapered shank and retaining the same in a suitabletapered tool arbor socket provided in the front or tool end of thespindle and fluid pressure actuated compound motor means for releasingthe tool arbor from the spindle arbor socket. I

4 Claims, 4 Drawing Figures PAIENIEUMNIQH 3,651,739

SHEET 2 [IF 4 Fig. 2

INVENTOR. HE/NZ l4. WOLF W6 QVM M ATTORNEYS.

MACHINE TOOL FIELD OF THE INVENTION This invention relates to a machinetool having a rotatable tool spindle and especially to the mechanism forconnecting and disconnecting a tool or a tool-carrying arbor to and fromthe spindle,

PRIOR ART Prior to the present invention it was customary to providemachine tools such as horizontal boring, milling and drilling machineswith spring-biased means for securing a tool arbor having a taperedshank in a tapered aperture in the front or I tool end of the rotatable,extensible and retractable tool spin- SUMMARY OF INVENTION The presentinvention provides a machine tool and more particularly a horizontalboring, milling and drilling machine comprising a rotatable, extensibleand retractable tool spindle having a tapered tool arbor receivingsocket in its front or tool end, spring-biased means for pulling andsecuring a tool arbor in the spindle socket, and fluid pressure-actuatedmeans including compound reciprocating motor means operable fromconventional shop or toolroom fluid pressure sources for releasing thetool arbor from the spindle socket which will be reliable in operationregardless of how tightly the tapered shank of the tool arbor is wedgedin the tapered spindle socket.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a horizontalboring, milling and drilling machine embodying the present invention;

FIG. 2 is a diagrammatic view, principally in elevation, showing thetransmission of the machine tool of FIG. 1, for moving the spindleheadmember relative to the column, for extending and retracting the spindlecarried by the head member and for rotating the spindle;

FIG. 3 is a fragmentary, sectional view, with portions in elevation,through the rear or non-tool portion of the tool spindle member of themachine tool of FIG. 1; and

FIG. 4 is a fragmentary, sectional view similar to FIG. 3 but showingthe front or tool portion of the tool spindle member and when joined toFIG. 3 along the dash-dot lines 33 produces a view showing essentiallythe entire spindle member.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT The preferred embodiment ofthe invention is a horizontal boring, drilling and milling machine Ahaving a horizontal bed portion B and a vertical column C extendingupward from or at one side of the bed. A spindlehead member D is guidedby the column C for vertical movement in a straight path and carries aspindle member E for supporting a tool. The spindle is rotatable aboutits longitudinal axis to rotate the tool, and is movable for extensionand retraction in a straight path along its axis of rotation, normal tothe path of movement of the head member. A compound slide F is supportedon the bed B for carrying the work being machined by the tool. Thecompound slide includes a bottom slide member G, hereinaftercharacterized as a saddle, movable in a horizontal straight path on thebed, transverse to the vertical column and spindle axis, and a top slidemember H, hereinafter characterized as a table, movable in a horizontalstraight path on the saddle, transverse to the saddle movement andparallel to the spindle axis.

The head member D moves along vertical guideways I0, 11 on the column,is counterweighted by a counterweight in the column C connected to thehead member by a chain 12, and is vertically positioned by a verticalhead screw 14 threaded through a nut 15, see FIG. 2, fixed in the headmember D. The screw 14 is rotatably supported but fixed against axialmovement at its upper end in a crown member K on the top of the column Cand at its lower end in a suitable bearing on the lower part of thecolumn. As shown, thehead screw 14 is enclosed by a verticallyextensible sleeve 16 for protection. A variable-speed, reversibleelectric drive motor 17, see FIG. 2, located at the top of the column Cprovides power for rotating the head screw 14 to raise and lower thehead member and a splined shaft 18 for extending and retracting thespindle member E relative to the head member. The splined shaft 18 isrotatably supported in the crown member K and extends downwardly throughthe spindlehead member D. A vertical gauge bar 19 extends from acantilevered part of the crown member or housing K on the verticalcolumn and cooperates with dial indicator 20, etc., to indicate thevertical position of the head member relative to a reference point onthe machine. A spindle drive motor 21 is carried by the head member Dfor driving the spindle in rotation.

The saddle G is movable along horizontal ways 22, 23 on the bed ,B bymeans including a saddle screw 24 fixed to the bed and a rotary nutcarried by the saddle and driven by a variable-speed drive motor 26carried by the saddle. Horizontal table ways on the top side of thesaddle extend transversely of the saddle ways on the bed, and supportthe table H for movement transversely of the direction of movement ofthe saddle. The table is moved by a table screw rotatably carried by thesaddle which screw has threaded engagement in a nut fixed to theunderside of the table. The table screw is driven by the slide drivemotor 26. A gauge bar 30 is associated with the table and a similargauge bar is associated with the saddle. The gauge bars each supportmeans to indicate the position of the slides relative to referencepoints on the machine. A pendant control panel or station P is suspendedin cantilevered fashion from a supporting conduit 33 in a convenientlocation adjacent the head member, saddle and table and carries themanual controls necessary for operating the machine.

The feed motor 17 is connected to one side of the housing or crownmember K and is selectively connectable to the spindlehead member D andthe spindle by a so-called continuous mesh drive including a two-speedplanetary transmission indicated generally by reference number 36 andclutches 38, 40. The output or drive shaft 42 of the motor 17 has a gear44 keyed thereto continuously in mesh with a ring gear 46 fixed to aplanet gear carrier or support 48 of the planetary speed changetransmission, The carrier 48 is rotatably supported by a rotatable shaft50 in the crown member K. The carrier or planet gear support 48 isselectively coupled to or uncoupled from the shaft 50 by an electricallycontrolled hydraulically actuated clutch 52. A wide-faced planet gear 54rotatably carried by the planet gear support 48 meshes with two sungears 56, 58. The sun gear 56 is fixed to the shaft 50 while the sungear 58 is freely rotatable on the shaft but can be selectivelyconnected by an electrically controlled hydraulically actuated clutch 60to the housing K so as to prevent rotation thereof. The sun gear 56 hasa slightly greater number of teeth than the sun gear 58.

A bevel gear 62 is fixed to the end of the shaft 50 and drives a bevelgear 64 having a spur gear 66 fixed to the hub thereof. Both gears arerotatable in the housing or crown K about the upper nonthreaded part ofthe head screw 14. The construction is such that the gear 62 can berotated at a relatively high speed by the motor 17 when the clutch 52 isactuated to connect the gear support 48 to the shaft 50 and the clutch60 is disengaged so that the sun gear 58 idles freely about the shaft50. Movement of the planet gear 54 about the sun gear 56 merely drivesthe sun gear 58 idly. The bevel gear 62 is driven at a relatively slowspeed when the clutch 52 is deenergized to disconnect the gear support48 from the shaft 50 and the clutch 60 is energized to hold the sun gear58 stationary. In such condition, orbiting of the planet gear 54 aboutthe fixed sun gear 58 drives the sun gear 56 at a very slow speed due tothe differential in the number of teeth between the two sun gears, andthereby drives the shaft 50 at the slow speed.

The bevel gear 64 and its associated spur gear 66 which are rotatableabout the upper part of the head screw 14 can be selectively coupled tothe screw 14 by the electrically controlled fluid-actuated clutch 38. Abrake disc 72 fixed to the screw 14 above the gear cluster can beclamped in fixed position against a stationary brake pad by a brakeactuator assembly 74 fixed to the housing K to secure screw 14 againstrotation and in turn to secure the head member D in a fixed positionrelative to the column C.

The gear 66 is continuously in mesh with a gear 76 fixed to the upperend of the spline shaft 18 and drives the spline shaft at all times thatthe gear 62 is driven. The lower end of the shaft 18 has a gear 80splined thereon which gear is rotatably supported in the spindleheadmember D and is continuously in mesh with a gear 82 fixed to a studshaft 84 also rotatably supported in the spindlehead member. The shaft84 has a bevel gear 86 keyed thereto which is continuously in mesh witha bevel gear 88 fixed to the drive member of the electrically controlledhydraulically actuated clutch 40. The driven member of the clutch 40 isrotatably supported on a shaft 92 rotatably supported in the spindleheadmember and the driven member of the clutch is keyed to the shaft 92 sothat the shaft can be rotated upon rotation of the gear 88 by engagementof the clutch 40. The shaft 92 has a gear 94 keyed thereto which gear iscontinuously in mesh with a gear 96 keyed or fixed on a spindle feedscrew 98 rotatably supported in the spindlehead and having threadedengagement with a nut 100 in a feed slide assembly N slidably andnonrotatably carried in the spindlehead and rotatably connected to therear part of the spindle E but fixed against axial movement relative tothe spindle. A brake disc 102 fixed to the gear 96 can be clamped infixed position against a stationary brake pad by a brake actuatorassembly 104 fixed to the spindlehead to secure the spindle feed screw98 against rotation and in turn the spindle E against axial movement inthe spindlehead member D.

Provision is made for manually moving or positioning the spindle Eaxially in the form of a hand wheel 106 at the front of the spindleheadmember and fixed to a shaft 108 rotatably supported in the spindleheadmember. The shaft 108 is continuously connected to a shaft 110 byreduction gears, designated generally as 112. The shaft 110 is in turnconnected by bevel gears 114, 116 to the shaft 92.

The spindle E is slidably keyed within a quill or sleeve member 120rotatably supported in the spindlehead member D and adapted to be drivenfrom the spindle drive motor 21 by a speed change transmission T. Theoutput shaft 122 of the motor 21 is connected to the input shaft 124 ofthe transmission T by continuously meshed gears 126, 128 keyed theretoand to the shaft 124, respectively. The output or drive member of thespeed change transmission is a gear 130 continuously in mesh with a gear132 fixed on the quill 120.

The particular construction of the transmission T forms no part of thepresent invention and is not herein described in detail. Suffice it tosay that it is of the constant mesh gear type in which the desiredoutput speeds are obtained by selectively connecting and disconnectingsuitable gears of the transmission to respective shafts upon which theyare rotatably supported by electrically controlled fluid-operatedclutches 134 to 141.

The spindle E can be selectively fed or moved axially as a function ofor in predetermined relation to its rotation by a gear drive including agear 144 continuously in mesh with a gear 146 ofa gear cluster 148 inthe transmission T. A second gear 150 of the gear cluster 148 iscontinuously in mesh with the output gear 130 of the transmission T. Thegear 144 is fixed to a shaft 152 rotatably supported in the spindleheadmember which shaft has a gear 154 fixed thereto and which is incontinuous mesh with a gear 156 keyed to a shaft 158 also rotatablysupported in the spindlehead member. The shaft 158 has a gear 160 fixedthereto and continuously in mesh with a gear 162 fixed to a shaft 164having gears 166, 168 keyed thereto. The gear 166 is continuously inmesh with a widefaced gear 170 rotatably supported in the spindleheadmember D and adapted to be selectively engaged by a gear 172 slidablykeyed to the spindle feed screw 98. The gear 172 is adapted to beshifted by electrically controlled solenoids between a neutral positionin which it is free to rotate with the spindle feed screw 98 or intoengagement with the gear 170 to rotate the spindle feed screw 98 in onedirection or engagement with the gear 168 to rotate the spindle feedscrew in the opposite direction. It will be understood that when thespindle screw 98 is driven from the motor 17, the gear 172 will be inits neutral or disengaged position and when the spindle feed screw 98 isdriven from the spindle E the clutch 40 will be disengaged.

The construction and operation of the compound slide F forms no part ofthe present invention and is not herein shown and described in detail.Suffice it to say that the slide members thereof are moved in theirrespective paths of movement by the variable speed reversible motor 26,as previously mentioned.

The motors 17 and 26 may be of any type but are preferably variablespeed silicon-controlled rectifier drives utilizing DC motors drivenfrom an alternating current power source.

The movements of the various machine tool elements such as thespindlehead D, the spindle E, the saddle G and the table H, as well asthe spindle rotation, etc, are controlled from the pendant station Pwhich comprises the manually operable switches, etc. required for theoperation of the machine.

The construction and operation of the machine tool A thus far describedis the same as that shown in my copending application, Ser. No. 882,502,filed Dec. 5, 1969, entitled Machine Tool to which reference is made fora more complete and detailed description of the machine.

The spindle E, see particularly FIGS. 3 and 4, comprises a tubularmember provided with an axially extending aperture 182, the forwardportion of which aperture preferably forms a socket 184 having a slighttaper to receive a tool or arbor R, for example the arbor of aconventional milling machine tool. The socket 184 terminates in acylindrical bore 186 adapted to receive a cylindrical portion or pilotof the tool arbor. The tool arbor is provided with an adapter or lockplug 188 threaded onto a tapped hole in the rear end of the arbor, priorto its assembly in the spindle, until a flange formed thereon abutsagainst the rearward end of the arbor. Alternatively, the so-calledadapter could be formed integrally with the arbor. The rear or left endof the adapter 188 is provided with a head 190 connected to the threadedportion of the adapter by a reduced portion or neck. The portion of thehead adjacent to the neck is frustoconical in configuration and providesa conical surface diverging rearwardly with respect to the axis of thespindle, which surface is adapted to be engaged by mechanism for bindingor locking the arbor in the spindle socket. The other or rear part ofthe head is also frustoconical in shape, but faces in the oppositedirection.

The mechanism shown for locking or binding the arbor R in socket 184comprises a collet 192 positioned within the bore 182 and connected tothe forward end ofa drawbar 194 in the bore 182, the rear end of whichis connected by a cylindrical member 196 to the front end ofa tubulardrawbar 198 extending to the rear of the spindle. The collet 192includes a plurality of spring or resilient fingers 200 each having aprojecting wedge-shaped portion provided with an inner inclined surfaceand an outer inclined surface. The inner surface of each wedge portionis inclined with respect to the spindle axis so as to diverge rearwardlyfrom the axis of the spindle and is adapted to engage the rearwardlydiverging surface on the adapter 188 when the collet 192 is in itsbinding or locking position. The outer inclined surface of each fingeralso diverges rearwardly and engages an annular rearwardly divergingabutment surface on a flange extending inwardly l0lO29 0135 from theinner wall of a bushing 202 fixed within the bore 182 of the spindle.The abutment surface on the bushing 202 diverges rearwardly with respectto the axis of the spindle with its acute angle of inclination less thanthe acute angle of inclination of the rearwardly diverging front orright conical surface of the adapter. The inner surfaces of the wedgeends of the collet fingers may be inclined, for example, at an angle ofto the axis of the spindle and the outer surfaces thereof atapproximately 20. The angles of inclination of the front or rightsurface on the head part 190 of the adapter and the flange of thebushing 202 correspond with those of the engaging inside and outsidesurfaces of the wedge portions of the collet fingers, respectively. Inthe binding position of the collet the wedge-shaped portion of each ofthe fingers 200 acts as a wedge, preferably a locking wedge, operatingbetween the fixed abutment surface on the bushing 202 carried by thespindle and the right inclined surface of the head 190 of the adapter188.

The collet 192 is continuously urged to a retracted or wedging positionto lock the arbor R in the spindle socket by a spring means M in theform of a plurality of oppositely facing heavy concavo-convex disc-likespring members in the bore 182 and interposed between the right or frontside of the member 196 and the left end of a tubular member 204 withinthe bore 182 and adjustably threaded into a second tubular member 206,the right or front end of which abuts the lefthand side of the bushing202. As can be appreciated, the spring means which holds the collet 192in locking position must be extremely strong because the vibration, etc.produced during the cutting operation tends to loosen the tool arborfrom the spindle socket. The disc-type spring M is particularlyapplicable because it requires a very limited movement for operation andcan be so constructed to produce the desired amount of force withoutnecessitating any change in its overall spindle dimensions.

To release the arbor R from the spindle socket 184, the collet 192 ismoved forwardly in the bore 182 to move the wedge portions of the colletfingers to a position forwardly of the shoulder forming the forward orright-hand side of the internal flange of the bushing 202. With thewedge portions of the fingers forward of this shoulder, the colletfingers will expand and permit the withdrawal of the arbor from thespindle socket 184. As the collet 192 is moved forwardly an abutmentmember 208 threaded in a tapered aperture in the right end of the drawbar member 194 and the forward portion which projects into the colletfunctions as an ejector or abutment member and strikes the rear orleft-hand end of the adapter 188 to unseat the arbor R from the socket184. The movement of the ejector 208, after it engages the end of theadapter 188, need only be sufficient to break the arbor away from itsseat in the socket 184. Preferably the inherent resiliency of the colletfingers 200 urge them into engagement with the head 190 of the adapterso that the arbor will be held by the fingers after it is unseated fromthe socket 184. To completely remove the arbor from the spindle socketthe operator need merely pull it outwardly to cause the fingers toexpand and release the arbor.

The collet 192 is moved forwardly with respect to the spindle member 202from its rearward locking or binding position in bore 182 to its forwardreleasing-and-ejecting position by the fluid pressure-actuatedreciprocating-type compound motor N having a pair of pistons designatedgenerally as 210, 212, slidable in suitable cylinder-like steppedcylinder apertures 214, 216 and 218, 220 in the three parts 222, 224,226 of the feed slide 226. The member 224 is of tubular shape and iscounterbored from each end to a substantially larger diameter to formthe right and external walls of the cylinder apertures 214, 218. Theleft wall of the aperture 214 is formed by the member 222 fixed to theleft end of the member 224 and having a cylindrical tubular portion 222aextending towards the right and of less outside diameter than theminimum inside diameter of the member 224. The piston 210 whichreciprocates on the tubular portion 222a has a tubular cylindricalportion 210a projecting to the right from the head portion 210b into thespace between the exterior of the cylindrical tubular portion 222a ofthe member 222 and the minimum diameter of the member 224. The headportion 210!) of the piston 210 has an external diameter which slidablyfits within the interior wall of the cylinder aperture 214. SuitableO-ring seals are provided between the piston 210 and the wall of thecounterbore which forms the cylinder aperture 214, between the piston210 and the minimum diameter portion of the member 224, and between thepiston 210 and the exterior of the tubular cylindrical portion 222a ofthe member 222. Pressure fluid, preferably oil, for moving the piston210 toward the right, as viewed in FIG. 3, is supplied through a conduit230 connected by a suitable fitting to the member 222 at a location tothe left of the piston 210.

The piston 212 is generally similar in construction to the piston 210and has a head portion 212a which fits within the cylinder aperture 218and a cylindrical tubular portion 212b which surrounds the cylindricaltubular part 2220 of the member 222 and projects into a counterbore inthe left end of the member 226 of the feed slide. The space between theright end .of the piston 210 and the left end of the piston 212 andbetween the exterior of the cylindrical tubular part 222a of the member222 upon which the pistons slide and the interior of the member 224forms the cylinder aperture 216 common to both motors and is maintainedfull of hydraulic fluid by an oil supply conduit 232 having a checkvalve therein for preventing reverse flow of oil. Pressure is created inthe cylinder aperture 216 for moving the piston 212 toward the right bymovement of the piston 210 toward the right. The left side of the pistonhead part 210b of the piston 210 is of considerably larger area than theright end face of the tubular cylindrical part 210a of the piston 210and because of the differential between these areas a high pressure canbe created on the left side of the piston head part 212a of the piston212 which is of relatively large area by the application of pressurefluid of relatively low pressure to the left side of the piston 210.

The right end of the piston 212 has an internal flange 212e, the rightside of which is adapted to engage the left end of a member 234 fixed tothe left end of the tubular member 198. The forward or right end of themember 234 has an external flange which is received within the interiordiameter of a sleeve member 236 having an internal flange at its leftend which limits movement of the member 234 and in turn the member 198to the left. The member 236 is adjustably threaded onto the left end ofthe cylinder member 180. The member 234 rotates with the spindle memberwhereas the piston 212 and its inwardly projecting flange 212e, which isadapted to abut the left end of the member 234, is stationary. Thecylinder apertures 214 and 218 to the right of the piston heads 210a and212a are both vented to a sump as by the conduits 240, 242 so as toprevent the accumulation of hydraulic fluid therein by similar conduitsopening into the right walls thereof.

When fluid pressure is admitted to the left side of the piston 210 thepiston moves towards the right building up pressure in the cylinderaperture 216 which in turn causes piston 212 to move toward the right.The flange 2126 of the piston 212 abuts against the left-hand end of themember 234 and pushes the drawbar assembly including the tubular member198 and the bar member 194 to the right. This in turn moves the collet192 and the ejector 208 to the right to release and unfreeze the toolarbor R from the spindle socket 184. Upon release of the pressure fluidin the conduit 230 the spring M returns the parts to their previous leftpositions. Pressure fluid is applied to the right side of the pistonhead 212a for the purpose of moving the flange 2120 free or clear of themember 234, thus providing a small clearance between the abuttingsurfaces of these members when they are in their respective left-handpositions. The purpose of this clearance is to eliminate the wear whichmight otherwise occur therebetween since the drawbar assembly, includingthe member 234, rotate with the spindle while the piston 212 preferablyremains stationary during the operation of the spindle.

Fluid pressure is supplied to the conduit 230 through asolenoid-operated valve supported in the rear end of the spindlehead ina suitable manner. The operation of the valve to control the flow ofpressure fluid to the conduit 230 in the direction to release thespindle arbor is preferably controlled by a selector switch 240 locatedat a convenient position on the pendant control station P where it isreadily accessible to the operator while he is holding the tool arbor inthe spindle socket. Attention is called to the fact that in machines ofthe character shown, the rear or left-hand end of the spindle is notwithin the reach of an operator at the tool end of the spindle.

When the operator wishes to attach a tool to the spindle, he moves theselector switch 240 to eject position to cause pressure fluid to enterthe rear or left end of the cylinder aperture 214. This moves the collet192 outwardly or to the right as viewed in the drawings. He then insertsthe tool arbor in the spindle socket and subsequently selects clampposition of the selector switch 240, whereupon the spring means Msecurely binds the tool arbor in the spindle socket and returns or movesthe piston assembly to its former position. When the operator wishes toremove the tool, he merely reverses the operation.

The motor assembly must provide not only adequate force to overcome thespring means M which holds the spindle arbor in the socket and which, aspreviously stated, must be substantial, but sufficient force to unfreezethe spindle arbor from the socket, which force is also substantialbecause of the low angle of taper employed in the socket. As can bereadily appreciated, the less the taper, the more securely will the toolarbor be held in the spindle socket. The present invention provides aconstruction wherein the necessary forces can be obtained with use ofthe usual shop compressed pressure fluid supply, while maintaining theoverall diameter of the motor means to a minimum. This is ofconsiderable practical advantage.

From the foregoing, it will be apparent that the object of the inventionhas been accomplished and that a new and improved machine tool has beenprovided having a spindle including a spring applied and power releasedlocking or binding mechanism for releasably securing an arbor or tool inthe spindle socket which is extremely reliable in operation and compactin construction. While the preferred embodiment of the invention hasbeen described in considerable detail, it will be apparent that theinvention is not limited to the construction shown and it is myintention to cover hereby all adaptations, modifications and changestherein which come within the practice of those skilled in the art towhich the invention relates.

lclaim:

1. In a machine tool, a movable spindlehead, a spindle member having anaxially extending aperture terminating at one end in a tapered socketadapted to receive a tool device, means for rotatably connecting saidspindle member to said spindlehead, a bar member supported within saidaxially extending aperture in said spindle member for limitedreciprocating axially thereof, a collet member connected to the end ofsaid bar member adjacent to said one end of said spindle member, meansproviding an inclined abutment surface on the interior of said spindlemember adjacent to said collet, said collet member including a radiallymovable portion with a first inclined surface for engaging and holding aportion ofa tool device inserted in said socket and received in saidcollet member and a second inclined surface for engaging and cooperatingwith said abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidmovable portion of said collet being inclined in the same generaldirection with respect to the axis of rotation of said spindle memberand converging in the direction away from said socket, spring means forapplying a first force on said bar member in the direction away fromsaid socket, a reciprocating-type pressure fluid-actuated motor meansfor applying a second force to said bar member in the direction towardssaid socket to overcome the first force applied by said springs, saidmotor means comprising a first cylinder concentric with the axis ofrotation of said spindle member, a first piston member having one sideof less area than that of the other side in said first cylinder, asecond cylinder arranged in tandem with respect to said first cylinderand concentric with the axis of rotation of said spindle member, asecond piston member in said second cylinder, conduit means operativelyconnecting adjacent ends of said first and second cylinders, means foroperatively connecting said second piston to said bar member, means forfilling said conduit means between said first and second piston memberswith fluid, and means for selectively supplying pressure fluid to saidfirst cylinder ofsaid motor means.

2. In a machine tool, a movable spindlehead, a spindle member having anaxially extending aperture terminating at the end in a tapered socketadapted to receive a tool device, means for rotatably connecting saidspindle member to said spindlehead, a bar member supported within saidaxially extending aperture in said spindle member for limitedreciprocating axially thereof, a collet member connected to the end ofsaid bar member adjacent to said one end of said spindle member, meansproviding an inclined abutment surface on the interior of said spindlemember adjacent to said collet, said collet member including a radiallymovable portion with a first inclined surface for engaging and holding aportion ofa tool device inserted in said socket and received in saidcollet member and a second inclined surface for engaging and cooperatingwith said abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidcollet being inclined in the same general direction with respect to theaxis of rotation of said spindle member and converging in the directionaway from said socket, spring means for applying a first force on saidbar member in the direction away from said socket, a reciprocating-typepressure fluid-actuated motor means for applying a second force to saidbar member in the direction towards said socket, said motor meanscomprising a cylinder assembly provided with first and second cylinderapertures arranged in tandem and concentric with the axis or rotation ofsaid spindle member and connected by a third aperture of lesser maximumdiameter, a first piston member in said first cylinder aperture havingan axial extension projecting into said third aperture, a second pistonmember in said second cylinder aperture, means for operativelyconnecting said second piston to said bar member, means for filling saidthird aperture between said first and second piston members with fluid,and means for selectively supplying pressure fluid to said firstcylinder aperture ofsaid motor means.

3. In a machine tool, a movable spindlehead, a spindle member having anaxially extending aperture terminating at one end in a tapered socketadapted to receive a tool device, means for rotatably connecting saidspindle member to said spindlehead, a bar member supported within saidaxially extending aperture in said spindle member for limitedreciprocation axially thereof, a collet member connected to the end ofsaid bar member adjacent to said one end of said spindle member, meansproviding an inclined abutment surface on the interior of said spindlemember adjacent to said collet, said collet member including a radiallymovable portion with a first inclined surface for engaging and holding aportion of a tool device inserted in said socket and received in saidcollet member and a second inclined surface for engaging and cooperatingwith said abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidmovable portion of said collet being inclined in the same generaldirection with respect to the axis of rotation of said spindle memberand converging in the direction away from said socket, spring means forapplying a first force on said bar member in the direction away fromsaid socket, a reciprocating-type pressure fluid-actuated motor meansreciprocable with but not rotatable with said spindle member forapplying a second force to said bar member in the direction towards saidsocket, said motor means comprising a first cylinder concentric with theaxis of rotation of said spindle member, a first piston member havingone side of less area than that of the other side in said firstcylinder, a second cylinder arranged in tandem with respect to saidfirst cylinder and concentric with the axis of rotation of said spindlemember, a second piston member in said second cylinder, conduit meansoperatively connecting adjacent ends of said first and second cylinders,means for operatively connecting said second pistion to said bar member,means for filling said conduit means between said first and secondpiston members with fluid, and means for selectively supplying pressurefluid to said first cylinder of said motor means. and holdmg 4. In amachine tool, a movable spindlehead, a spindle member having an axiallyextending aperture terminating at one end in a tapered socket adapted toreceive a tool device, means for rotatably connecting said spindlemember to said spindlehead, a bar member supported within said axiallyextending aperture in said spindle member for limited reciprocationaxially thereof, a collet member connected to the end of said bar memberadjacent to said one end of said spindle member, means providinganinclined abutment surface on the interior of said spindle memberadjacent to said collet, said collet member including a radially movableportion with a first inclined surface for engaging and holding a portionof a tool device inserted in said socket and received in said colletmember and a second inclined surface for engaging and cooperating withsaid abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidcollet being inclined in the same general direction with respect to theaxis of rotation of said spindle member and converging in the directionaway from said socket, spring means for applying a first force on saidbar member in the direction away from said socket, a reciprocating-typepressure fluid-actuated motor means reciprocable with but not rotatablewith said spindle member for applying a second force to said bar memberin the direction towards said socket, said motor means comprising acylinder assembly provided with first and second cylinder aperturesarranged in tandem and concentric with the axis of rotation of saidspindle member and connected by a third aperture of lesser maximumdiameter, a first piston member in said first cylinder aperture havingan axial extension projecting into said third aperture, a second pistonmember in said second cylinder aperture, means for operativelyconnecting said second piston to said bar member, means for filling saidthird aperture between said first and second piston members with fluid,and means for selectively supplying pressure fluid to said firstcylinder aperture of said motor means.

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1. In a machine tool, a movable spindlehead, a spindle member having anaxially extending aperture terminating at one end in a tapered socketadapted to receive a tool device, means for rotatably connecting saidspindle member to said spindlehead, a bar member supported within saidaxially extending aperture in said spindle member for limitedreciprocating axially thereof, a collet member connected to the end ofsaid bar member adjacent to said one end of said spindle member, meansproviding an inclined abutment surface on the interior of said spindlemember adjacent to said collet, said collet member including a radiallymovable portion with a first inclined surface for engaging and holding aportion of a tool device inserted in said socket and received in saidcollet member and a second inclined surface for engaging and cooperatingwith said abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidmovable portion of said collet being inclined in the same generaldirection with respect to the axis of rotation of said spindle memberand converging in the direction away from said socket, spring means forapplying a first force on said bar member in the direction away fromsaid socket, a reciprocating-type pressure fluid-actuated motor meansfor applying a second force to said bar member in the direction towardssaid socket to overcome the first force applied by said springs, saidmotor means comprising a first cylinder concentric with the axis ofrotation of said spindle member, a first piston member having one sideof less area than that of the other side in said first cylinder, asecond cylinder arranged in tandem with respect to said first cylinderand concentric with the axis of rotation of said spindle member, asecond piston member in said second cylinder, conduit means operativelyconnecting adjacent ends of said first and second cylinders, means foroperatively connecting said second piston to said bar member, means forfilling said conduit means between said first and second piston memberswith fluid, and means for selectively supplying pressure fluid to saidfirst cylinder of said motor means.
 2. In a machine tool, a movablespindlehead, a spindle member having an axially extending apertureterminating at the end in a tapered socket adapted to receive a tooldevice, means for rotatably connecting said spindle member to saidspindlehead, a bar member supported within said axially extendingaperture in said spindle member for limited reciprocating axiallythereof, a collet member connected to the end of said bar memberadjacent to said one end of said spindle member, means providing aninclined abutment surface on the interior of said spindle memberadjacent to said collet, said collet member including a radially movableportion with a first inclined surface for engaging and holding a portionof a tool device inserted in said socket and received in said colletmember and a second inclined surface for engaging and cooperating withsaid abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidcollet being inclined in the same general direction with respect to theaxis of rotation of said spindle member and converging in the directionaway from said socket, spring means for applying a first force on saidbar member in the direction away from said socket, a reciprocating-typepressure fluid-actuated motor means for applying a second force to saidbar member in the direction towards said socket, said motor meanscomprising a cylinder assembly provided with first and second cylinderapertures arranged in tandem and concentric with the axis or rotation ofsaid spindle member and connected by a third aperture of lesser maximumdiameter, a first piston member in said first cylinder aperture havingan axial extension projecting into said third aperture, a second pistonmember in said second cylinder aperture, means for operativelyconnecting said second piston to said bar member, means for filling saidthird aperture between said first and second piston members with fluid,and means for selectively supplying pressure fluid to said firstcylinder aperture of said motor means.
 3. In a machine tool, a movablespindlehead, a spindle member having an axially extending apertureterminating at one end in a tapered socket adapted to receive a tooldevice, means for rotatably connecting said spindle member to saidspindlehead, a bar member supported within said axially extendingaperture in said spindle member for limited reciprocation axiallythereof, a collet member connected to the end of said bar memberadjacent to said one end of said spindle member, means providing aninclined abutment surface on the interior of said spindle memberadjacent to said collet, said collet member including a radially movableportion with a first inclined surface for engaging and holding a portionof a tool device inserted in said socket and received in said colletmember and a second inclined surface for engaging and cooperating withsaid abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidmovable portion of said collet being inclined in the same generaldirection with respect to the axis of rotation of said spindle memberand converging in the direction away from said socket, spring means forapplying a first force on said bar member in the direction away fromsaid socket, a reciprocating-type pressure fluid-actuated motor meansreciprocable with but not rotatable with said spindle member forapplying a second force to said bar member in the direction towards saidsocket, said motor means comprising a first cylinder concentric with theaxis of rotation of said spindle member, a first piston member havingone side of less area than that of the other side in said firstcylinder, a second cylinder arranged in tandem with respect to saidfirst cylinder and concentric with the axis of rotation of said spindlemember, a second piston member in said second cylinder, conduit meansoperatively connectIng adjacent ends of said first and second cylinders,means for operatively connecting said second pistion to said bar member,means for filling said conduit means between said first and secondpiston members with fluid, and means for selectively supplying pressurefluid to said first cylinder of said motor means. and holding
 4. In amachine tool, a movable spindlehead, a spindle member having an axiallyextending aperture terminating at one end in a tapered socket adapted toreceive a tool device, means for rotatably connecting said spindlemember to said spindlehead, a bar member supported within said axiallyextending aperture in said spindle member for limited reciprocationaxially thereof, a collet member connected to the end of said bar memberadjacent to said one end of said spindle member, means providing aninclined abutment surface on the interior of said spindle memberadjacent to said collet, said collet member including a radially movableportion with a first inclined surface for engaging and holding a portionof a tool device inserted in said socket and received in said colletmember and a second inclined surface for engaging and cooperating withsaid abutment surface on the interior of said spindle member, saidabutment surface and said first and second inclined surfaces of saidcollet being inclined in the same general direction with respect to theaxis of rotation of said spindle member and converging in the directionaway from said socket, spring means for applying a first force on saidbar member in the direction away from said socket, a reciprocating-typepressure fluid-actuated motor means reciprocable with but not rotatablewith said spindle member for applying a second force to said bar memberin the direction towards said socket, said motor means comprising acylinder assembly provided with first and second cylinder aperturesarranged in tandem and concentric with the axis of rotation of saidspindle member and connected by a third aperture of lesser maximumdiameter, a first piston member in said first cylinder aperture havingan axial extension projecting into said third aperture, a second pistonmember in said second cylinder aperture, means for operativelyconnecting said second piston to said bar member, means for filling saidthird aperture between said first and second piston members with fluid,and means for selectively supplying pressure fluid to said firstcylinder aperture of said motor means.